use print_function
Replace old format style
Fix miss imports
private key convert str to bytes if python3
connection closing
Conforms to pep8
Pyflakes is quite
Add python versions to TravisCI
Travis CI doesn't support Python 3.0, 3.1 and 3.4

I don't know why Travis CI doesn't support Python 3.0, 3.1 and 3.4.
I guess 3.4 is just released.

This is the Travis log.

Using worker: worker-linux-6-1.bb.travis-ci.org:travis-linux-1

Applying updates
$ git clone --depth=50 git://github.com/gengo/gengo-python.git gengo/gengo-python
Cloning into 'gengo/gengo-python'...
remote: Counting objects: 427, done.
remote: Compressing objects: 100% (181/181), done.
remote: Total 427 (delta 261), reused 406 (delta 240)
Receiving objects: 100% (427/427), 76.35 KiB | 0 bytes/s, done.
Resolving deltas: 100% (261/261), done.
Checking connectivity... done.
$ cd gengo/gengo-python
$ git fetch origin +refs/pull/31/merge:
remote: Counting objects: 46, done.
remote: Compressing objects: 100% (16/16), done.
remote: Total 34 (delta 24), reused 28 (delta 18)
Unpacking objects: 100% (34/34), done.
From git://github.com/gengo/gengo-python
 * branch            refs/pull/31/merge -> FETCH_HEAD
$ git checkout -qf FETCH_HEAD
$ source ~/virtualenv/python3.1/bin/activate
/home/travis/build.sh: line 216: /home/travis/virtualenv/python3.1/bin/activate: No such file or directory

The command "source ~/virtualenv/python3.1/bin/activate" failed and exited with 1 during setup.

Your build has been stopped.
format for Python 2.6
Raise request of Requests version

Bacause, Requests include urllib3. Older urllib3 doesn't work on Python3.
new style format in setup.py
fix indentation
Merge pull request #31 from narusemotoki/py3

Python3 Ready